钛合金及其复合材料氧化产物多尺度结构调控及超级电容性能

Regarding the current problem that the fabrication cost of electrode materials for high performance supercapacitors is very high, a new method is proposed to produce electrode materials for supercapacitors with low cost in this project. The means is that high-temperature oxidation is performed on titanium alloys and composites prepared with solidification route. The multi-scale control is conducted on the compositions and structures of the oxides formed on the surfaces of titanium alloys and composites. In macro and micron scales, oxidation processes and the compositions and microstructures of titanium alloys are adjusted. In nano scale, nano-reinforcement is introduced to titanium alloys. Through multi-scale control, oxide structures on titanium alloys and composites can be regulated and further electrode materials for supercapacitors with high performance can be obtained. The research work will help us master the regulation of oxide structures and reveal the formation mechanism of nanooxides. In addition, it is hope to detect the influence of the compositions and structures of the oxides on their supercapacitor properties and built the relation between the compositions and structures of the oxides and their supercapacitor properties. This work will have important theoretical value on the development and application of electrode materials for supercapacitors with low cost, high energy density and high cycle stability.

针对目前高性能超级电容器电极材料制备成本高的问题，本项目提出对凝固路线获得的钛合金及其复合材料进行高温氧化处理以制备低成本超级电容器电极材料。拟多个尺度上调控钛合金及其复合材料氧化产物成分与结构，通过从宏观上调整氧化工艺，微观上调整钛合金成分与组织，纳观上引入纳米增强相以达到调控钛合金及其复合材料基底上氧化物成分与结构的目的，进而获得良好的超级电容器电极材料。通过本项目的研究，掌握钛合金及其复合材料基底上氧化物结构的调控规律，揭示纳米氧化物的形成机制，探明氧化物成分与结构对其超级电容性能的影响机制，构建氧化物成分与结构与其超级电容性能的相关性，为低成本、高储能和高循环稳定超级电容器电极材料的开发与应用提供理论支持。

近年来，超级电容器发展成了新一代的储能元器件，在能源储存的领域占得日益重要的地位。然而，水热等路线制备氧化物类电极材料存在制备成本高、难以量产等明显不足，本项目提出提出对凝固路线获得的钛合金进行高温氧化处理以制备低成本超级电容器电极材料。本项目采用真空非自耗电弧熔炼技术和快速凝固技术制备了多个成分的钛合金片和薄带(Ti-Al系，Ti-Fe系，Ti-Al-Fe系等)，随后对其进行高温氧化处理，制备自支持电极，并探讨其超电容性能。.电弧熔炼和快速凝固的Ti-8Al合金在不同工艺下的氧化产物均为金红石型TiO2和Al2O3，二者共生生长，呈纳米尺度的棒状形貌，且有集束特征。金红石型TiO2容易生长成棱形形状，Al含量偏低，致使最终共生生长产物呈现棒状形貌。随着氧化时间和氧化温度的增加，氧化产物的量随之增加，并且比电容也随之增大。在三电极体系下，在680℃下氧化100h制备的TiO2/Al2O3复合电极性能最好，氧化后的电弧熔炼Ti-8Al合金薄片试样在电流密度为1mA cm-2时，比电容为400mFcm-2；氧化后的快速凝固带状试样在电流密度为1mA cm-2时，比电容为645mFcm-2。这两种电极的循环寿命都很长，并随着循环次数的增加，比电容整体呈上升趋势。.电弧熔炼Ti-15Fe合金经680℃/100h氧化后，氧化产物为带棱线的粗短棒状的共生生长型TiO2和Fe2O3复合物。该复合材料电极具有良好的电化学性能，在电流密度为1mA cm-2时，比电容达到315mF cm-2。经3000次循环后比电容保持率为225%(5mA cm-2)。快速凝固的Ti-15Fe合金薄带经680℃/100h氧化后，氧化产物的组成及形貌均没有发生明显的变化。该复合材料电极在电流密度为1mA cm-2时，比电容达到370mF cm-2。经800次循环后比电容的保持率达到700%(5mA cm-2)。.Ti-10Fe-6Al合金片和薄带经680℃/100h氧化后，氧化产物为共生生长型TiO2/Fe2O3/Al2O3复合材料，该复合材料呈现出有集束特征的棒状形貌，这些纳米棒由平均直径为90nm的纳米颗粒构成。Ti-10Fe-6Al合金薄带氧化产物在电流密度为40μA cm-2时，比电容达到10500 μF cm-2，5000次循环后，比电容保持率为79.9% 。